We propose to develop a new diagnostic test to substantially improve the definitive diagnosis of ectopic pregnancy (EP) . This new test would complement serial quantitative beta-hcg and ultrasound testing, currently used for diagnosing EP, and provide earlier and more accurate diagnosis of this potentially fatal condition. The new test is based on a recently discovered marker, a unique pregnancy-related protein (PRP) secreted by the proliferative trophoblast during the early stages of pregnancy. PRP can be immunologically detected by monoclonal antibody, known as A137, developed at Aspen Diagnostics. PRP is present in he cervical mucous of pregnant women with intrauterine implantation but appears to be absent in women with extrauterine implantation. The ability to predict the location of a regnancy could provide earlier, non-invasive diagnosis of EP, bypassing costly ultrasound r invasive diagnostic laparoscopy. Furthermore, rapid and accurate diagnosis and treatment could lower the rate of tubal rupture thereby lowering morbidity and mortality associated with EP. Early diagnosis and treatment of EP may also improve future fertility of the affected patient.